This is my Ultimate Collector Series Octuptarra Tri-Droid. It is based off of and inspired by the large Octuptarra Tri-Droid seen in the Christophsis Miniland section of Legoland. If you want to see pictures of this, go to Reto Geiger's brickshelf (these are the pictures I used as models when building). My Tri-Droid is much bigger than that seen at Legoland, having a sphere that is 52 studs across rather than 30 of the other. So far, this is largest creation I've ever constructed, containing 12845 pieces. There are around 8000 pieces just in the head alone.
I started off from the middle and worked my way outward, first building the ring with the 2x2 45 degree angle sloped bricks. I then created a hexagonal shape and attached it to the center ring. For the legs, I planned on building one, and then copying and it twice to make the construction easy on myself. However, I faced one main problem with the legs: incorporating the blue spheres at the joints. I needed to create a sturdy structure, while having cool details such as the sphere. I figured out a way to run a technic beam through the sphere (and at the same time being connected to the sphere) and then connect the beam to attachments within the legs.
Once the legs were finished and the foundation for the Octuptarra's body was laid down, I moved on to the head. I used a program called Bram's Sphere Generator, the same that I used for my Droid Control Ship, to generate the sphere. It was 52 studs across with a solid interior. I also colored the sphere to have the classic CIS appearance. After adding the guns, I connected the head to the "neck" with a long technic cross axle that ran deep within the head and the "neck" of the Tri-Droid. A couple little details later, and I was finished! This is one of my favorite creations that I've ever built, and one of my favorite ships from the Clone Wars. Thanks for viewing, and please rate and comment!

About this creation

Part of the neck, connects to the head

The inside of the sphere before coloration; those large plates on the inside contain tons of connections to the surrounding plates
This is a picture of the completed head, minus the cross axle and its attachments
Here is my large Octuptarra compared to my smaller one

Quoting Daniel Mayhew
Really excellent job. Must have taken forever to design. I'd love to see it in real life.

TLG had already created a model for me to use as a template so the designing wasn't that bad. And I wish I could build this out of real Lego! It just isn't in my budget, I mean it would be around $1500 to build this model alone. If you haven't noticed most of my builds are in LDD, if I had the resources, I would build all of them! Anyways, thanks for your comment, and maybe one day I'll surprise you, and have an actual real life version of this Tri-Droid!